The present invention is a protective parking pad with temperature insulating properties and constructed of compressible and resilient material which will compress under the weight of a vehicle parked on it and having an amount of resistance to compression so as to support the vehicle tire in a manner that minimizes the amount of distortion of tire shape.
Rubber vehicle tires suffer from a problem known as xe2x80x9cflatspottingxe2x80x9d which is a permanent distortion in the shape of a tire. A vehicle tire is manufactured to have an equal measurement of radius from the center of the axle to a point on the outer edge of the tread at any point around the circumference of the tread. A tire manufactured in this manner will have a round shape which will allow the axle to maintain a constant distance above the road and provide a smooth ride for the vehicle. When a vehicle is parked, the weight of the vehicle deforms the lowermost portion of the tire where the weight of the vehicle is being supported. The rubber in the tread and sidewall in this lowermost area is compressed and deformed by the weight of the vehicle. The casing and belts of a tire are bonded to the tread and sidewalls. The compressed and deformed areas of the tread and sidewalls exert pressure on the casing and belts, forcing the casing and belts to deform as well. When the vehicle is driven, the tire becomes heated by friction and expands. The constant flexing of the rubber, caused as each portion of the tire receives the weight of the vehicle as the tire rotates, allows the tire to return to its original round shape, aided by the resiliency of the belts and casing.
The problem, known as xe2x80x9cflatspottingxe2x80x9d, occurs when the deformation of the tire, which is caused when the vehicle is parked, becomes permanent. The permanent deformation results in a smaller radius of the vehicle tire at the point where the deformation exists. The permanently deformed tire is no longer round and the result is a bumpy ride and substantially reduced handling performance.
The permanent deformation occurs when a vehicle remains parked in one position for an extended period of time. The areas of the rubber tread and sidewalls which are supporting the vehicle will deform under the weight. The rubber tread and sidewalls are bonded to the belts and casing of the tire and the deformed areas of the tread and sidewalls exert constant pressure on the belts and casing, to which they are bonded, to deform the belts and casing to the same shape as the tread and sidewall. If the vehicle is driven after a short period of time, for example a time not exceeding several days, the resiliency of the belts and casing will force the tire to return to its original round shape as it is warmed and flexed during use. If the vehicle is not driven for a long period of time, for example one month, the belts and casing gradually lose their resiliency and become permanently deformed under the constant pressure from the tread and sidewalls. When the vehicle is driven, the belts and casing do not force the tire to return to its original round shape. The tire is permanently damaged.
The effect of tire deformation is exacerbated by other factors. One factor is the range and rate of temperature change. Once vehicle tires have been warmed by use, parking on the cool floor of a garage rather than a warm outdoor parking area, will increase the amount of compression of the rubber tread and sidewalls. The loss of heat in the area of the tire which is in contact with the cool floor, is the same area of the tire which has been deformed by the weight of the vehicle. The extent to which the rubber is compressed is increased by the drop in temperature. Another factor is the softness of the tire itself. A softer tire will compress more and therefore deform more than a hard tire. A third factor is the height of the sidewall relative to the width of the tread. The new style of performance tires feature short sidewalls to increase sidewall stiffness. In this type of tire, the stiff sidewall retains its shape to a greater extent in the area where the vehicle weight is being supported and the pressure from the weight of the vehicle is concentrated on the tread portion causing the deformation of the tread portion to be more pronounced; thereby increasing the extent of deformation of the belts and casing. The factors, including the rate and range of temperature change and tire construction work to decrease the amount of time required to cause permanent, as opposed to temporary, deformation of tire belts and casing, and a permanent xe2x80x9cflatspotxe2x80x9d.
The problem of xe2x80x9cflatspottingxe2x80x9d occurs most often with vehicles which are used on an occasional basis. The worst problems occur with high performance cars used by enthusiasts. The high performance tires operate at high temperatures and high performance tires are softer, with short sidewalls, to enhance performance. Often, the cars are kept in a garage and used occasionally. All of the factors which contribute to flatspotting are present. Typically, flatspotting is prevented by lifting the vehicle onto a set of stands, so that it is supported on its frame and not on its tires. This method is time consuming and impractical. Also, while the vehicle is on the stands, the springs and shock absorbers are fully extended which causes undue wear to these components.
A need exists for a device to prevent tire flatspotting, without the necessity of lifting the vehicle. In addition to the need of car enthusiasts, other situations where vehicles remain parked for extended periods of time will benefit from the present invention. Equipment on trailers, construction equipment, farm equipment, military vehicles and aircraft could all benefit from the present invention as well as any vehicle in a long term parking situation.
The present invention comprises a temperature insulating pad of compressible and resilient material, such as microcellular water blown polyether based polyurethane foam constructed to a density so as to provide resiliency characteristics matching the weight carried by a vehicle tire, and constructed with a top side, a bottom side, a front edge a back edge and two side edges. The top and bottom sides being parallel to each other and the back and side edges being perpendicular to the top side and bottom side. The front edge being beveled to form a sloping surface from the top side toward the bottom side and the portion of the top side at the back edge having a raised area along the back edge. The pad being constructed with a thickness from the top side to the bottom side appropriate to allow partial but not complete compression, when a vehicle is parked with a tire resting on the protective parking pad.
The present invention addresses the problem of tire xe2x80x9cflatspottingxe2x80x9d by providing a plurality of protective parking pads which may be positioned on the floor of the vehicle parking area so that each vehicle tire rests on a protective parking pad when the vehicle is parked in its usual position.
When the vehicle is parked on the protective parking pads, the pads partially compress and conform to the round shape of the tires, thus distributing the vehicle weight over a large area of the tread and sidewall surface in a shape duplicating the normal curvature of the tire; thereby reducing the extent to which the tire is deformed. The pads insulate the tires from rapid transfer of heat from the tires which occurs when the tires directly contact the parking area floor. The rapid transfer of heat from the tires, increases the contraction of the rubber tread and sidewalls. The increased contraction increases the pressure on the belts and casings of the tires; thereby adding to the degree of deformation which has occurred in the area of the belts and casings upon which the vehicle weight is resting. The undesirable effects of rapid heat transfer from the tires and of deformation of the tires, are avoided by the present invention. The tires will remain in their normal round shape and xe2x80x9cflatspottingxe2x80x9d will not occur regardless of the length of time during which the vehicle remains parked on the protective parking pads.